Drier drums comprising annular shell air deflecting collars



DRIER DRUMS COMPRISING ANNULAR SHELL AIR DEFLECTING COLLARS Filed Feb. 27, 1967 L. G. JANETT Sept. 10, 1968 2 Sheets-Sheet l m 2A m m INVENTOR. LESLIE GEORGE JANETT ATTORNEY FIG. 3 (PRIOR ART) L. G. JANETT Sept. 10, 1968 DRIER DRUMS COMPRISING ANNULAR SHELL AIR DEFLECTING COLLARS 2 Sheets-Sheet 2 Filed Feb. 27, 1967 INVENTOR. LESLIE GEORGE JANETT 7400144 SMW ATTORNEY ABSTRACT OF THE DISCLOSURE Each drier drum of a plurality comprising a web drying apparatus has its far end or untended side provided with a shell extension at about the drums periphery and axially outwardly. The extension is attached to the drum end by the'same bolts used in its construction or, it can be spaced in close relation relative the drum periphery and exteriorly supported.

This invention relates to a web drying apparatus improvernent eifecting a more uniform drying of a web moving therethrough. More particularly, the improvement constitutes the addition of a shell to the drier drums far end, usually termed the drive side of a machine, as an air diverter means assisting in drawing out pocketed moist air formed between adjacent drier drums.

In the drying of a web suchas paper or similar material, a continuous sheet or web is passed over a plurality of drying drums, the positioning of which form so-called pockets formed by a combination of a drying web, drier cylinders, and carrier felt or fabric web, which eventually are filled with moist air arising from both the carrier belt and the web such as paper traveling therealong over the heated surfaces of the drums. The steam heated drying rolls are quite large in order to provide a large heating surface for a quick evaporation of moisture from both the drier felts and the webs. Since a large number of such drier rolls are necessary, even in a single pass drying operation, the many formed intermediate pockets are soon occluded with a moisture laden atmosphere that is difficult to move out. It is obviously desirable that the moist air from these pockets be removed as it tends to be reabsorbed by the carrier felt or fabric and therethrough by the process drying web making drying imperfect and creating a need for larger and larger apparatus.

The moisture pockets are formed especially within the ends of the drier drum lengths. This is so since the web ends are further away from the pocket interior, and drum side effects tend to move adjacent air out leaving the interior more moist. The uneven drying, obviously, is not desired for the web to be acceptable for subsequent processing should be evenly dried throughout its width.

Among means presently used for eliminating moisture occlusion between the rolls is a partially successful one of inserting a nozzle into the area of such pockets and blowing dry hot air therethrough. This is not fully successful since the effectiveness of the blown air in jet form is blunted and variously deflected by the heavy moisture laden air in the pocket, plus a radial. operating turmoil of air effected by the rotation of a drum end, particularly at its far side. This portion of a drier drum, in its assembly, has the end secured to the drum by closely spaced large bolts and nuts. The protrusion of the bolts and nuts beyond the end of the rotating cylinder end simulates an impeller, or more descriptively, the floats of a centrifugal fan wheel effecting a radial or right angular (to the drum) movement of adjacent air, especially with the assistance of strengthening ribs on the face of the drum ends. Each drum in combination with adjacent drums United States Patent "ice 3,400,469 Patented Sept. 10, 1968 forms a wall of such radially moving air with the result that the moist air pockets have difiiculty moving out or in being moved out rearwardly, and only toward the tending or threading-up direction of the machine.

The front or tending side of the drier drums present no such problem. This is because of the tending side drum construction. A grooved flanged rim on the tending side that is provided for carrying the threading ropes of the machine is of such width that it extends substantially outwardly beyond the eylinders end into the working area, and because it surrounds the circumferential plurality of nuts and bolts it acts as a shell diverter of any air about the end of the cylinder. As described, this is not the condition at the opposite end or drive side of the drier drums where the open assembly of the circular grouping of extending nuts and bolts and end reinforcement upon rotation act as a fan impeller agitating air in a plane at right angles to the drum forming an occluding wall of air diflicult to get through.

This invention advantageously provides for an improvement to drier drum ends preventing the formation of the vertical wall of turbulent air to thus enable a ready displacement and removal of rising moist air from inbetween the drier rolls or drums. This is effected by an attachment or by adjacent positioning of a diverter shell element to the far end of each drier drum. Such an element in conjunction with each drum would prevent the formation of radially moving air and instead deflect its radial direction of movement driving it laterally away thus keeping the pocket open for moist air removal. With the occluding air wall out of the way any standard means of keeping pockets clear of moisturized air, such as the Grewin nozzle apparatus, becomes eflicient and useful and effective in the drying of paper web. The diverter element itself generally comprises a shell or shield with faired internal surfaces to promote laminar air flow and diversion, the shell extends away from the drier drum a substantial distance to thus carry any air thereabout away from the drum. The end encompassing shield can be stationary or it can be secured to the drum end by the end bolts and nuts rotating with the drum in operation. The invention will now be fully explained in the following description with the accompanying drawings, where:

FIGURE 1 represents in perspective a portion of a web drying apparatus showing a formed pocket from which moisture is continually desirably removed;

FIGURE 2 is an end view of a web drying apparatus not having an air diverter shown in FIGURE 1;

FIGURE 3 is a sectional view, in part, along line 3-3 of the pocket between drums and the end occluding blanket of air formed by the drum end without the diverter of FIGURE 1;

FIGURE 4 is a section taken across line 44 of FIG- URE 1 showing different support means for the diverter element; and

FIGURE 5 is an end detail in section of a drier drum of FIGURE 4.

A web drying apparatus generally comprises a great number of drier drums arranged in a manner so as to provide for as long a surface contact for passing web as is possible yet permit access to them. This ordinarily means that the drier drums are positioned in tapered bottom staggered groups of a multiple number in the longitudinal direction of the apparatus. And when the drier felt is passed about a lower intermediate drum, it and the web passing thereover forms a pocket. This void or space or pocket becomes filled with moist air which can be reabsorbed unless it is removed. As stated herein, dry heated air is forced through surh pockets at high velocities but it is not fully effective since it is, to a substantial extent, deflected by a curtain of vertically moving air at the untended apparatus side or the far side, for the 3 operator. Thus as shown in FIGURE 1, the pocket 10 is formed by any three drier drums such as 11, 12, 13 and by the passing drier felt or fabric 15.

Ordinarily, the pocket 10 becomes substantially filled with moist air, the moisture being emitted from the drying of the passing felt 16 and from the drum surfaces as well as from the web which wets the felt through contact. The moisture laden air cannot move out because of an occluding end blanket of air created, as shown by the arrows in FIGURES 2 and 3, by the impeller action of the end nuts and bolts 18 holding the closure ends 17 to the drum cylinder bodies of the driers. Sometimes the drum ends 17 have radial reinforcing 19 or similarly shaped elements such as hand-hole covers and the like which add and increase the velocities of air in a radial direction, as shown. Along with the neighboring drums there is thus created a wall of turbulent air through which the pocketed moist air cannot flow and merely remains in the pocket becoming saturated to be again regained by the passing felt, which in turn is rewetted rather than dried.

Referring again to FIGURE 1 it has been discovered that the tending side (front or threading-up side) does not have as concentrated an amount of slow moving moist air about the various drier drums as further within a pocket and still further toward the opposite side. This phenomenon, it has been found, was due to the annular threadingup grooved rope sheave rims 21 being attached to the tending end of the drums 11, 12, 13 acting as diverters. Whatever air the radial reinforcing 19 pumps outwardly is deflected or diverted by the threading-up ring 21 and it is forced out and away in a longitudinal manner in a direction axial to the cylinder into the atmosphere. At the same time its outward flows pull along with it adjacent inner atmosphere from about the drums. This phenomenon is shown in FIGURE 4. A somewhat similar arrangement is advantageously provided by this invention for an improved or similar moving action of air from the far end or drive side of the drums for the express reason of eliminating the occluding end blanket of air to tend to equalize the flows of moisture laden air to the tending side and drive side, respectively, and thereby to improve the drying uniformity of the web and increasing drying capacity of the apparatus.

Opposing the threading-up guide rim is a shell 24, as shown in FIGURES 1 and 4, that is turned out longitudinally in the direction of the axis of the drier drum. The

turned shell 24 catches and diverts adjacent atmospheric fiow from the end outwardly and away. Each drum, then, equipped with such an end air diverter prevents the establishment of an occluding air curtain and the moisture laden atmosphere within the pocket is diminished in size because of end flows. .The inner space now can be flushed out with dry warm air. The shell 24 can be. radially secured during assembly of the drier drum by means of the same bolts and nuts 18 as shown in FIGURES 1 and 5. Or, the diverter can be spaced about a drier end as a spaced fixed collar as indicated in FIGURE 4. In the latter instance it would have to be held by an adjacent support (not shown) by some means as rivets 30 or bolts, etc.

What is claimed is:

1. A drying apparatus for paper web comprising a plurality of staggered web drier drums in a series, a carrier fabric traveling over them for guiding said web, said carrier fabric with said web forming space pockets in between correlated staggered drums whichbecome stagnant with moist air, and said drums having positioned at one end a threading sheave and at the other an annular shell extending generally axially away therefrom a distance sufficient to enclose drum end structures, said shells being adapted to prevent an establishment of radial air movement effected by said drum end structures during rotation thus occluding the escape of said pocketed moist air.

2. In the apparatus of claim 1 where the said annular shell is attached to said drum and rotates therewith.

3. In the apparatus of claim 1 where the annular shell is spaced about the periphery of said drum end and is stationarily supported by an adjacent support, and an adjacent means for the support of the aforesaid shell.

References Cited UNITED STATES PATENTS 2,299,459 10/1942 Chatain 34--1 11 XR 2,651,114 9/1953 Hornbostel 34-l24 2,700,094 1/1955 Hosack 16589 XR JAMES NV. WESTHAVER, Primary Examiner.

A. D. HERRMANN, Assistant Examiner. 

